Adhesion of electrolessly deposited nickel-phosphorus on alumina ceramic : an assessment of the current status

Literature data on the adhesion of electrolessly deposited Ni(P) films on alumina ceramic substrates are reviewed in this paper. The influences of conditions of successive etching, nucleation and metallization processes on adhesion are discussed as well as the effect of subsequent annealing treatments. Also, a comparison is made with the adhesion of electrolessly deposited Ni(B) and Cu layers. In general, too little information is provided by most authors on the adhesion measurement conditions and procedures. It has been concluded that etching is more important for adhesion than nucleation, metallization and annealing, and it is commonly believed that mechanical interlocking is the dominant adhesion mechanism. However, bilayer experiments with electrolessly deposited Ni(P) and Cu suggest that the intimacy of interfacial contact plays an additional role. This may indicate that van der Waals or other interfacial interactions significantly contribute to adhesion. In order to obtain further insight into the adhesion mechanism, a fracture mechanics characterization is suggested. Modern surface analytical techniques should be applied to study interfaces and fracture surfaces.